Extended Dot Cluster Marker for High-speed 3D Tracking in Dynamic Projection Mapping

2017 ◽  
Author(s):  
Yoshihiro Watanabe ◽  
Toshiyuki Kato ◽  
Masatoshi ishikawa
Keyword(s):  
High Speed ◽  
3D Tracking ◽  
Projection Mapping

scholarly journals High-Speed Dynamic Projection Mapping onto Human Arm with Realistic Skin Deformation

2021 ◽  
Vol 11 (9) ◽  
pp. 3753
Author(s):  
Hao-Lun Peng ◽  
Yoshihiro Watanabe
Keyword(s):  
User Interfaces ◽  
High Speed ◽  
Target Surface ◽  
Human Vision ◽  
Surface Model ◽  
Projection Mapping ◽  
Skin Deformation ◽  
Human Arm ◽  
Conventional Methods ◽  
Joint Tracking

Dynamic projection mapping for a moving object according to its position and shape is fundamental for augmented reality to resemble changes on a target surface. For instance, augmenting the human arm surface via dynamic projection mapping can enhance applications in fashion, user interfaces, prototyping, education, medical assistance, and other fields. For such applications, however, conventional methods neglect skin deformation and have a high latency between motion and projection, causing noticeable misalignment between the target arm surface and projected images. These problems degrade the user experience and limit the development of more applications. We propose a system for high-speed dynamic projection mapping onto a rapidly moving human arm with realistic skin deformation. With the developed system, the user does not perceive any misalignment between the arm surface and projected images. First, we combine a state-of-the-art parametric deformable surface model with efficient regression-based accuracy compensation to represent skin deformation. Through compensation, we modify the texture coordinates to achieve fast and accurate image generation for projection mapping based on joint tracking. Second, we develop a high-speed system that provides a latency between motion and projection below 10 ms, which is generally imperceptible by human vision. Compared with conventional methods, the proposed system provides more realistic experiences and increases the applicability of dynamic projection mapping.

scholarly journals EFFICIENT MULTI-VIEW 3D TRACKING OF ARBITRARY ROCK FRAGMENTS UPON IMPACT

2020 ◽  
Vol XLIII-B2-2020 ◽  
pp. 589-596
Author(s):  
D. E. Guccione ◽  
K. Thoeni ◽  
A. Giacomini ◽  
O. Buzzi ◽  
S. Fityus
Keyword(s):  
3D Reconstruction ◽  
High Speed ◽  
Visual Hull ◽  
Post Processing ◽  
Tracking Accuracy ◽  
3D Tracking ◽  
Rock Fragments ◽  
Fragmentation Test ◽  
Impact Fragmentation ◽  
Improved Performance

Abstract. This paper presents a new methodology to accurately obtain 3D rotational velocities of blocks and fragments. Four high speed cameras are used to capture the scene. An additional two tilted mirrors are used to multiply the number of views. Hence, a total of six different viewing perspectives can be used to track translational and rotational velocities in 3D. The focus in the current work is on the rotational velocities, as tracking of the translation is generally straightforward. A common outline tracking algorithm based on the visual hull is adapted. The visual hull is further meshed using triangular elements to approximate the shape of the object. This 3D reconstruction is then used to track the 3D motion of the object. However, the accuracy of the results strongly depends on the accuracy of the 3D reconstruction which is mainly influenced by the number and position of the available views. In any case, the 3D reconstruction from the visual hull is only an approximation and significant errors can be introduced which influence the tracking accuracy. Hence, an in-house post-processing algorithm based on the knowledge of the real geometry of the object, which can generally be accurately determined after a test, was developed. The improved performance of this new post-processing method is shown by controlled spinning tests. Finally, results of a real example of an impact fragmentation test are discussed.

Lumipen 2: Dynamic Projection Mapping with Mirror-Based Robust High-Speed Tracking against Illumination Changes

2016 ◽  
Vol 25 (4) ◽  
pp. 299-321 ◽  
Author(s):  
Tomohiro Sueishi ◽  
Hiromasa Oku ◽  
Masatoshi Ishikawa
Keyword(s):  
Visual Feedback ◽  
High Speed ◽  
Moving Objects ◽  
Vision System ◽  
Visual Quality ◽  
Temporal Delay ◽  
Projection Mapping ◽  
Speed Tracking ◽  
Illumination Changes

Dynamic projection mapping (DPM) is a type of projection-based augmented reality that aligns projected content with a moving physical object. In order to be able to adjust the projection to fast motions of moving objects, DPM requires high-speed visual feedback. An option to reduce the temporal delay of adjusting the projection to imperceptible levels is to use mirror-based high-speed optical axis controllers. However, using such controllers for capturing visual feedback requires a sufficient amount of illumination of the moving object. This leads to a trade-off between tracking stability and quality of projection content. In this article, we propose a system that combines mirror-based high-speed tracking with using a retroreflective background. The proposed tracking technique observes the silhouette of the target object by episcopic illumination and is robust against illumination changes. It also maintains high-speed, accident-avoidant tracking by performing background subtraction in an active vision system and employing an adaptive windows technique. This allows us to create a DPM with an imperceptible temporal delay, high tracking stability and high visual quality. We analyze the proposed system regarding the visual quality of the retroreflective background, the tracking stability under illumination and disturbance conditions, and the visual consistency relative to delay in the presence of pose estimation. In addition, we demonstrate application scenarios for the proposed DPM system.

Characteristics of Spatter in Micro-Drilling of Metal Sheet by Pulsed Nd:YAG Laser

2016 ◽  
Vol 10 (6) ◽  
pp. 874-881 ◽  
Author(s):  
Yasuhiro Okamoto ◽  
◽  
Hibiki Yamamoto ◽  
Akira Okada ◽  
Keyword(s):  
Initial Velocity ◽  
High Speed ◽  
Gas Flow ◽  
Thermal Damage ◽  
Drilling Process ◽  
3D Tracking ◽  
Workpiece Surface ◽  
Video Cameras ◽  
High Speed Video ◽  
Micro Drilling

In laser cutting and drilling process, molten material was scattered as spatter, which deteriorates the surface integrity of a workpiece because of the thermal damage. It is expected that the control of assist gas flow can reduce the adhesion of spatter. In order to investigate the improvement method of thermal damage due to the adhesion of spatter, it is required to clarify characteristics of spatter. Therefore, a method was developed to collect and analyze spatter based on the use of high-speed video cameras in the laser micro-drilling process, and the characteristics of spatter movement were numerically investigated by CFD analysis. The scattering velocity and angle of the spatter were investigated by recognizing and tracking spatter with the high-speed video observation. The movement of spatter was observed by using two high-speed video cameras, and analyzed by using a two-direction tracking method, in which the 3D tracking lines of spatter particles were reconstructed in the forward and backward frames, and the actual trajectory of individual spatter particle was obtained by averaging those tracking lines. These measurements revealed that the initial velocity of spatter was mainly distributed from 52 m/s to 200 m/s with an average velocity of 129 m/s. The initial angle of spatter was mainly distributed between 0 and 30 degrees from the workpiece surface in the upward direction. There was little correlation between the initial velocity and angle of spatter. The diameter of spatter was mainly distributed from 1μm to 4μm with an average diameter of 3.7μm. It is important to use the processing conditions achieving the smaller spatter diameter in order to reduce the thermal damage caused by spatter. Although coaxial assist gas flow has an influence on the spatter behavior, that time period is very short. Therefore, it is important to control the spatter behavior outside of the coaxial assist gas flow by using an additional gas flow to prevent the thermal damage to the workpiece surface.

drop

2021 ◽  
Vol 4 (2) ◽  
pp. 1-8
Author(s):  
Sadam Fujioka
Keyword(s):  
Computer Graphics ◽  
Computer Animation ◽  
High Speed ◽  
New Technique ◽  
Optical Illusion ◽  
Interactive Art ◽  
Projection Mapping ◽  
Art Installation ◽  
Ultra High Speed ◽  
A New Technique

This paper describes an interactive art installation titled "drop." It is the first artwork using the Waterdrop Projection-Mapping (WPM) system, which animates levitating waterdrops. With this artwork, the anno lab team infuses physical characteristics into computer graphics and materializes them as tangible pixels. WPM consists of a waterdrop generator and an ultra high-speed projector. The team uses an ultra high-speed projector to cast stroboscopic spotlights mapping on waterdrops to create an optical illusion of animating each waterdrop individually. This is a new technique to show computer animation by animating levitating waterdrops. This technique explores a new horizon to create animations with tangible pixels that the viewer can touch physically.

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